debian/control.in: drop needless libdbus-glib-1-dev dependency

As libdbus-glib-1-dev was deprecated in Bug#895291 [1], and dbus-glib is not used at all, so it was removed from debian/control.in.

This commit fixes Bug#955855 unnecessarily Build-Depends on deprecated dbus-glib. [2]

Note that dbus-glib is used when enchant zemberek provider is enabled, but actually disabled by --disable-zemberek in debian/rules, so it is ok to remove them.

[1] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=895291 [2] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=955835